Package and storage of apples



Sept. 23, 1952 PLAGGE 2,611,709

PACKAGE AND STORAGE OF APPLES Filed May 14, 1949 INVENTOR. HOMER H. PLAGGE, DECEASED BY ALMA R. PLAGGE, ADWIWSTRATR/X Patented Sept. 23, i952 UNITED sTArEs ATENT OFF! PACKAGE AND sroimenor APPLES Homer ILPlagge, deceased,late of Ames, Iowa,

by Alma. R. Plagge, administratrix dc bonis non,

Ames, Iowa, assignor, by direct and mesne assignments, of one-half to Iowa State College a Research Foundation, Inc.,' Ames, Iowa, a. cor- I 'poration of Iowa, and one-half to The Goodyear zTire & Rubber Company, Akron, Ohio, a corpo- I I rationof Ohio Applicati May 1;, 1949 ,'Serialllo.93,386

This invention relates to the preservation and storage of fruit; and more particularly apples and pears, referred to generally herein as pomes. Such fruits areharvested in late summer or the fall and it hasb'een custdmary-to keep the'min storage rooms at relatively low temperatures for use throughout the winter. By early or 'late spring they have lost suificient moisture to cause shriveling, and various blights, etc. have taken their toll. 1

Storage in air tight containers would preserve the moisture content, but'all' such fruits give off carbon dioxide during storage, and too high a. concentration of carbon 'dio'xide in" the atmosphere in which they are stored causes physiological break-downofthe fruit. To satis factorily store such" fruit it should be maintained at a relatively low temperature in an atmosphere of controlled. carbon-dioxide conr'zentratiom' and the loss of moisture should be prevented.

Such storage delays the maturing of the fruit. This is advantageous because fruit of retarded maturity is more resistantthan' fullymatured fruit to the bruising to which it is subjected in shipping and subsequent handling. By storing at 30 to 38 F. in an atmosphere of controlled carbon-dioxide content, the maturing of the fruit may be retarded as much as a month or more. Consequently, it may be stored longer and marketed later than is now customary, if desired.

are advantageously stored at about 36 F. and pears at about 30 to 31 F. Although for apples the carbon-dioxide content of the air within the storage container is preferably about to percent, for pears a concentration from 5 to 2001' per cent is satisfactory. Therateat which carbon dioxide is given off by a fruit varies with the age of the fruity and the temperature at which it is stored, so it is difiicult. to maintain constant conditions within 'a'fstorage container.

' rclaim. (cl. 994.71)

ployed for fruit storage.

well for the purposes of this invention.

Any film liner sufliciently impervious to the passage of carbon dioxide to maintainj'the de-j sired carbondioxide concentration within'th'e container, may be used. Rubber hydrochloride film suitably plasticized is preferred., Film of; vinyl chloride-vinyl acetate copol'ymer, suitably plasticized may be used; ,Thincellulose acetate ,film suitably coated. may beemployed. Other, 'films will be found suitable.

The suitability of afilm does not vary with the size of the container. Film which-maintains Y the desired carbon-dioxide content in a bushel of fruit stored under certain conditionswill be The optimum storage conditions vary. .Apples For instance, freshly picked apples give arr-car.

bondioxide much more readily than appleswhich are three or four-weeks old. If packaged ime mediately after picking, the carbon dioxidecontent of the air in the storage container during the first several weeks will be much higher than subsequently. For. this reason 'it-rnay bejde sirable to postpone packing the apples in containers until after the initial period of several weeks in which carbon dioxide is rapidly evolved.

The storage container used for packaging fruit according to this invention is air pervious, such as, for example, a basket or crate or loosely fabricated barrel or box of the type now generally emequally satisfactory for lining a barrel for storageof the-same fruit under the same conditions.

The gauge and plasticizer content of rubber hydrochloride film control its carbon-dioxide permeability. The following table illustrates the difference in carbon dioxide content maintained in storage containers filled with freshly picked apples stored at 36 F. after storage for different periods. The different rubber hydrochloride films are identified by code letters which are explained in the paragraph following the table. The films were not sealed, but the edges were simply folded tight to one another.

CO: concentration in apple containers during I e liner may be sealed I around the fruit, but this is not necessary. b cause a tight fold such as a confectioners fold; --will hold the edges of the'film together equally In coding the films, the number preceding the letter indicates the gauge of the film, 100 gauge being .001 inch thick. P6 represents film plasticized with,.. .10..parts dibutyl. .phthalate and 5.. parts ofirubber hydrochloride The=FF film which is more permeable to carbon dioxide contains parts of methoxyethyl oleate and 15., parts of dibutyl sebacate per 100 parts of rubber hydrochloride. The other three films =in;the., above table have the same composition butthe .10 first is .0014 inch thick, the ,second;is ;0012;inch1 thick, and the third is .00075 inch..thicki., The next two films which are ofthe :more permeablei composition are .00075 ands-.0012 inch .'thick,-:re:

spectively. The first film in thegaugesrecorded lfii is too impermeable for appleivcontainer liners; 1 The other film in the thinner gauge, that is film .00075 inch thick and containing; 15partssomethoxyethyl oleate and 15 parts of'dibutyl sebacate per 100 parts of rubber hydrochloridel-re-:

tains only sufiicient carbon dioxide to maintain apreferredcontent of this gas WhiChriS somewhat- CO2 permeability of rubber hydrochloride 'films 40 c. c. 00;] FilnL'. Thickness 10D i'nJ/Zi hourss;

l met t .00075 2,962 FF? .5 .00100 2,722 .OOMO. 2,285.., .00170 1, 936 if 0 0 ,0065 PL. 00140 586,7

The above table illustrates the extent to which the escape .of. carbon TdlOXid may be :controlled by using films of different thickness and films of different plasticizer content. Films of still other plasticizer content have difierent carbon-dioxide permeability:-

The liner prevents loss of moisture vapor. Moisture-vapor loss is low with all rubber hydrochloride film. Other films may have low moise tare-vapor transmission, or may be coated to give them low moisture-vapor transmission. Rubber hydrochloride films is preferredbecauseit per-' mits', relatively high carbon-dioxide diifiusion withllow moisture loss.

Tests have shown that for Jonathan,Red Delicious, andWinesap apples at a temperature of 362?. and a relative humidity of 86, a carbondioxide content of about seven per cent is preferred and five to eleven per cent is usable with advantageous results. For pears a carbondioxidebontentof. five per icent; up to20 or perhaps125 -perrcent ispermissible. Thus, for pomes, generally, a carbon-dioxide content within the limits of five and 25 per cent is required. Different contents within this range are maintained by films of idiffrent gauge and composition.

The drawingillustrates a gas-permeable box I measuring ll iiinches wide by 10% inches high, andl'l inchesflldng, filled with 125 Golden Delicioust-apples-i .after being lined with FF film 3.-, Afitersfilling the apples into the lined containers=the=edgeszs=of the liner were overlapped andfifoldedg with -twisting to prevent subsequent separation. On-storage for three months at 36 1?: therfilmbreduced the weight loss to onehalf or one-quarter of normal, and almost en- ;tirely-elirninated shriveling. The results of individual paper wraps andga rubber-hydrochloride liner were compared; A .box of paper-wrapped aDDl& :.-af:ter-erstorage under the described conditionslryielded ones'bad; apple,:only-;11 good apples and.-1l3shriivelled applese The apples identically stored inuthezicontainerzwith the rubber hydrochlorideH5FFrliner-,=averaged-5 slightly shrivelled, 33-green (retarded maturity); andiST-yellow (prime teating gcondition) stora e containersw, for other: fruits; may be lined with suitable film to maintain a. higherthanenormal levehofccarbon;fdioxide .within' the containemat whatever:temperature and humidity are desirabledomthat ifraiit."

What is-lelairnedlds:;-

Ages-permeable astorage container having :un- Y Wrappedc apples; therein: andprovided .2 with. a

tight: liner offrubher; hydrochloride. film 'no more than ZOQLZjiIlCh: thickzandzcontaining 15 parts of methoxyethyl'oleate and-15 parts of; dibutyl seba v cate per loflmpartsrof rubbenhydrochloride.

, ALMA Rf. PLAGGE'r, Administratrix. demonis nons of the estate of Homer Plagge deceased.

REFERENCES LCITED The following;-;references.:arevof record in 'the Mildew P ke insPjN vember-.1940, pa e, 48,,

article entitled fNew Celery lrjeserving- Tech-1 niquel "Pliofilm in ThePreservation of. Florida 1=ruits.. and *Vegetables, Bulletin 369, February 1942,1by

Mdde'mTrickaging, June .1948, pages. 163, "164, 

